Filter press with endless filter cloth

ABSTRACT

A filter press of plate-and-frame type or recessed plate type is provided with an endless filter cloth which is passed under each of filter elements and over a filter element adjacent thereto in zigzag form. Rollers and drive means for moving the filter cloth in the zigzag form are also provided. The filter cloth is passed through a washing vessel disposed on the frame of the filter press in which the surface of the cloth is cleaned by washing means such as wash liquor ejecting pipes.

United States Patent Kurita 51 Sept. 12, 1972 [54] FILTER PRESS WITHENDLESS FILTER CLOTH [72] Inventor: Ken-ichiro Kurita, 36-4, S-chome,

Senriyama-nishi, Suita, Japan [22] Filed: March 11, 1970 [21] Appl. N0.:18,459

[52] US. Cl. ..2l0/225 [51] Int. Cl. ..B0ld 25/32 [58] Field of Search..100/198, 199; 210/225-230, 216, 297, 387

[56] References Cited UNITED STATES PATENTS 3,360,130 12/1967 Kaga..210/225 2,969,148 1/1961 l-lirs ..210/387 X FOREIGN PATENTS ORAPPLICATIONS 1,080,461 8/1967 Great Britain 100/ 198 PrimaryExaminer-Reuben Friedman Assistant Examiner-T. A. GrangerAttorney-McCarthy, De Paoli & OBrien I 57] ABSTRACT A filter press ofplate-and-frame type or recessed plate type is provided with an endlessfilter cloth which is passed under each of filter elements and over afilter element adjacent thereto in zigzag form. Rollers and drive meansfor moving the filter cloth in the zigzag form are also provided. Thefilter cloth is passed through a washing vessel disposed on the frame ofthe filter press in which the surface of the cloth is cleaned by washingmeans such as wash liquor ejecting pipes.

4 Claims, 7 Drawing Figures FIG! I nventor KEN-IL'H/RO KUR/m 9 1C and 1544.

A Home PATENTED E 12 I972 3.690.462

sum 3 or 4 lnvenlor KEN-lC/l/RO K URITA Attorneys FILTER PRESS WITI-IENDLESS FILTER CLOTH BACKGROUND OF TI-IE INVENTION The present inventionrelates to a filter press, more particularly to a filter press of thetype in which a continuous sheet of filter cloth employed for all of thefilter elements in common is moved in endless manner.

In a filter press, the cake deposited during filtering operation isremoved from the filter cloth. When the cloth wears out due to repeatedoperations and becomes no longer fit for use, there is a need to replaceit with a new cloth. In a filter press of conventional type, however,the filter cloth, which is attached to the respective filter platesseparately, requires a long period of time for replacement and istherefore very uneconomical and inefficient. In addition, due to thetroubles of replacement, the filter cloth is not replaced as frequentlyas desired and the wear of the cloth deteriorates the efficiency of thepress, while the worm out cloth can not be used again even if it iswashed after replacement. These are the problems which further aggravatethe above-described economy of the filter press.

BRIEF SUMMARY OF THE INVENTION spite of the deposition of filter cakethere is no need to replace the filter cloth but the cloth once put onthe press can be used over and over until a structural defect developstherein. This merit ensures marked improvement in the efficiency andeconomy of the filter press.

The features of and improvements in the present invention will becomeapparent from the following detailed description with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation showing anembodiment of the filter press in accordance with the present invention.

- FIG. 2 is a front view in vertical section taken along the line IIIIin FIG. 1; v

FIG. 3 is a front view in vertical section taken along the line III-IIIin FIG. I;

An object of the present invention is to provide a filter press in whicha continuous sheet of filter cloth is hung on filter plates irrespectiveof the number of the plates, the structure being such that when thefilter cloth gets soiled by filtration the soiled cloth is wound up atone side to run out clean cloth at the other side so as to make cleancloth available all the time for improved efficiency and economy of thefilter press.

Another object of the present invention is to provide a filter press inwhich a continuous sheet of filter cloth I is hung on filter plates inendless fashion irrespective of the number of the plates and in whichthe filter cloth is adapted to be moved by a motor or the like whendesired so that a portion of the cloth used for filtration can bereplaced with a clean portion of the cloth. In accordance with thestructure of this filter press, the used portion of the cloth is movedout of filtering section into a washing vessel for automatic washingoperation so as to effect filtration with a clean cloth all the timeuntil a structural defect of the cloth such as a rent or hole makes itno longer fit for use, utmost efficiency and economy thus being ensured.

The filter press as hereinreferred to includes both plate-and-frame typeand recessed plate type.

In accordance with the present invention, filter cloth is hung onrespective filtering units each comprising a plate and frame orrespective recessed-type filter plates in zigzag manner so as to form acontinuous strip of cloth and when washing is required the strip ismoved to provide a new filtering portion for the filtering faces of theplates. Accordingly, as compared with separate sheets of filter clothattached to the respective filter plates, renewal of the filtering facecan be effected extremely easily and quickly with resultant improvementin efficiency and economy.

The continuous strip of filter cloth, being endless, can be so disposedthat part thereof passes through a washing vessel. When desired,therefore, the filter cloth is driven into the washing vessel forwashing and the cleaned portion of the cloth is brought to the filteringsection so as to effect filtration with best efficiency. In

FIG. 4 is a side elevation in vertical sectiontaken along the line IV-IVin FIG. 2;

FIG. 5 is a side elevation showing another embodiment of the filterpress in accordance with the present invention;

FIG. 6 is a front view in vertical section taken along the line VI-VI inFIG. 5; and w FIG. 7 is a sectional view taken along the line VII- VIIin FIG. 6.

DETAILED DESCRIPTION'OF THE PREFERRED EMBODIMENTS Referring to theembodiment in FIG. 1, designated at l are side bars of the filter presswhich are disposed in parallel at the front and rear as seen in FIG. I,with opposite ends of each side bar supported on frames 2 on the rightand left. Filter plates 4 and filter frames 5, alternately arranged in arow, are hung on these two side bars 1 with respective opposite arms 7and 8 supported on the side bars 1 in movable manner. As shown in FIGS.1 and 2, each of the filter plates 4 is provided with projections 10 onthe opposite sides thereof, while it will be seen form FIGS. 1 and 3that each of the frames Sis provided with projections l l on itsopposite sides. The projections 10 and 11, facing each other, of theadjacent plate 4 and frame 5 are linked together by means of bolts 12and nuts 13 to limit the separation between the plate and frame.Further, the plate 4 and frame 5 on the extreme right and left arerespectively connected to a movable end plate 3 and the frame 2 in thesimilar manner. Designated at 14 is a hydraulic cylinder for moving themovable end plate 3 back and forth. The ram 15 thereof is connected tothe movable end plate 3. Numeral 16 indicates a washing vesselpositioned on one of the frames 2 and provided with a drain l7 and asuitable number of rotatable guide rollers 18. The other frame 2carrying the hydraulic cylinder 14 is further provided with a pair ofcylinders 19 disposed in the front and rear in FIG. 1. Provided at theforward end of piston 20 of each cylinder 19 is a tension roller 24whose shaft 21 is movably inserted into a slot 23 in a guide plate 22.Filter cloth 25 is passed over the tension roller 24, lower rollers 26attached to the undersides of the respective filter plates 4, upperrollers 27 mounted on the upper sides of the respective filter frames 5and further along guide rollers 18 positioned within the washing vessel16 on the frame 2. In this'manner the filter cloth- 25 is disposedbetween respective plates 4 and frames 5 in zigzag and endless fashion.When required, the tension roller 24 is driven, for instance, by amotor. The hydraulic cylinder 14 is built in the other frame 2, on whichis mounted a support 28 for supporting upper extension 3 extendingbackward from the upper portion of the movable end plate 3. The tensionroller means described above is mounted on the upper extension 3'. Thewashing vessel 16 is provided with ejecting pipes 29 for discharging awashing liquor such as water, ammonia or the like. These ejecting pipes29 are arranged in desired positionsin the washing vessel 16 anddirected toward'the front and rear faces of the filter cloth 25 to besent forward by guide rollers 18. When desired, the ejecting pipes 29may be equipped with nozzles at the ejecting holes. Designated at 30 isa guide roller and at 31, a

scraper.

' The operation of the embodiment in FIG. 1 will now I be described.When the movable end plate 3 is pushed forward by the ram of thehydraulic cylinder 14 to bring respective plates 4 and frames 5 togetherfor filtration with the cloth 25 brought into pressing contact with theopposite faces of the plates 4 and frames 5, the cylinders 19 areactuated to move the tension roller 24 backward and keep the filtercloth 25 taut which tends to slack due to the-forward movement of theend plate 3. The filtering operation is then .carried out. When theoperation is completed, the movable end plate 3' is retracted by the ram15 of the hydraulic cylinder 14 to release the plates 4 and frames 5 oneafter another to allow the filter cake to drop downward. At this timethe tension roller 24 is advanced by the forward movement of thecylinder 19, whereby the filter cloth 25 held taut during operation isloosened as the end plate 3 is moved backward for the removal of thefilter cake. When the filter cloth 25 is moved in the direction of anarrow in the drawing by driving the tension roller 24, the filter cakeis removed from the surface of the filter cloth 25 by means of thescraper 31' and the cloth is sent by the tension roller 24 into thewashing vessel 16, where the surface is cleaned with a liquor dischargedfrom the ejecting pipes 29. The scraper 31 may be used when desired.

FIG. 5 shows an embodiment in which the filter plate and filter frame asemployed in the foregoing embodiment are made into a filter plate 6, asingle plate, which functions also as a filter frame. The filter plate 6is socalled recessed-plate type and has a main part 6a one surface ofwhich is provided with projections 32, the other surface being formedwith a recessed portion 33 of a suitable depth defined by the outerperipheral edge 6b As in the embodiment shown in FIG. 1, arms 9 providedon the opposite sides are supported on two parallel side bars 1 inmovable manner. Each of a number of the plates 6 thus supported isprovided, at a lower portion, with a pair of links 34 mounted on a pivot35 on each of the front and rear sides thereof. The ends of therespective links 34 are connected to a shaft 63 carrying lower rollers26 and disposed at a lower position between each two adjacent plates 6,the plates 6 being associated with one another by these links. It willbe seen in FIG. 5 that the plates 6 at the right and left end positionsare respectively connected by links 34 to the movable end plate 3 andone of the frames 2 in like manner. Filter cloth 25 is passed over twoguide rollers 44 mounted on the frame 2 and movable end plate 3, alongupper rollers 27 and lower rollers 26, and along the guide rollers 18 inthe washing vessel 16. The filter cloth is therefore hung on anddisposed between respective filter plates 6 in zigzag and endless form.Driven sprockets 36 mounted on the upper opposite sides of one of theframes 2 are driven through chains 38 by drive sprockets 37 mounted on alower drive shaft 64 which is driven by an unillustrated motor. Thedrive shaft 64 and follower shaft 65 driven by the shaft 64 are eachprovided, at the opposite ends, with two sprockets 66 for driving thelower and upper rollers. The upper roller 27 and lower roller 26 arerespectively provided with drive sprockets 39 and idle wheels 40 mountedon shaft 70 and shaft 63. With respect to each two adjacent rollers, theposition relationship between the drive sprocket 39 and the idle wheel40, one to be positioned inwardly of the other, is reversed. At each ofopposite ends of the upper rollers 27 and lower rollers 26, therefore,the sprocket 39 and wheel 40 are disposed inwardly or outwardly of eachother alternately to provide inner and outer chain lines 41 and 42 aswill be described below. The two inner and outer chain lines are eachassociated with sprockets 39 and idle wheels 40 alternately atrespective rollers. At each end of one roller, the drive sprocket 39 isassociated with one of the chain lines while theidle wheel 40 isassociated with the other chain line. The outer chain 41 in engagementwith the outer sprockets 66 on each of the follower shaft 65 and thedrive shaft 64 is passed over the drive sprockets 39 and idle wheels 40which are positioned along the outer chain line, whereas the inner chain42 engaged with the inner sprockets 66 is passed over the drivesprockets 39 and idle wheels 40 along the inner chain line. Accordingly,each of the upper rollers 27 and lower rollers 26 is provided with therotation of the drive shaft 64 and follower shaft 65 by way of the outerchain 41 or the inner chain 42 with which its drive sprocket 39 isengaged. The outer chain 41 for driving the upper rollers'27 is alsoreeved around two other auxiliary sprockets 43, one independentauxiliary idle wheel 69 and two common auxiliary idle wheels 67 whichare positioned along the outer chain line, while the inner chain 42 ispassed around one auxiliary sprocket 68, one independent auxiliary idlewheel 69 and the two common auxiliary idle wheels 67 which are alignedon the inner chain line. The outer chain 41 for driving the lowerrollers 26 is passed around one auxiliary sprocket 43 and fourcornmonauxiliary idle wheels 67 which are positioned on the outer chain line.The inner chain 42 is passed over the four common auxiliary idle wheels67 which are positioned on the inner chain line. The upper rollers 27and the lower rollers 26 are driven in the same direction by the driveshaft 64.

The operation of this embodiment will be described. When the movable endplate 3 is pushed forward by the ram 15 of the hydraulic cylinder 14 andthe respective filter plates 6 are brought into pressing contact withone another for filtration, the filter cloth 25 is pressed against thesurfaces of the plates 6, so that one surface of each filter plate 6,namely the recessed portion 33 serves as a cake chamber. When filtrationis completed, the movable end plate 3 is retracted by the ram 15 torelease the filter plates from one another to allow the filter cake todrop therefrom. in the case where there arises a necessity to replacethe filter cloth 25 with a new cloth 25 after a period of operation, theplates 6 are brought into separated position and the driven sprocket 37is rotated by the motor to drive the upper rollers 27 and lower rollers26 in the same direction. As a result, the cloth 25 is sent into thewashing vessel 16 along the upper and lower rollers 27, 26 and two guiderollers 44 and subjected to a suitable wash liquor for cleaning in thesame manner as in the foregoing embodiment. In accordance with thisembodiment, the slack of the cloth during filtration is eliminated bythe rollers 26 which are lowered when the links 34 are brought intoclosed position.

The projections 32 on the filter plates 6 are provided in the shape suchas of truncated pyramids and recessed portions are formed between theprojections. Designated at 45 is an inlet 45 for a liquid to befiltered. When the filter plates are brought together, the respectiveinlets 45 form a continuous tubular passage which is separated fromfiltrate outlets 46 to be described later. The prefilt supplied ispassed through the inlet 45 and a hole 49 which is communicatedtherewith and admitted into the cake chamber 33 of the plate through anopening 47. The prefilt introduced into the cake chamber 33 is furtherpassed through the filter cloth 25 disposed between the filter plates 6into the filtering side of the adjacent plate 6. The filtrate then flowsbetween the projections 32 into a hole 50 through an opening 48 andreaches an outlet 46 which is formed into a tubular passage. Thefiltrate is thus recovered.

I claim:

1. A horizontal filter press comprising:

A. a plurality of recessed filter plates serving as both filter platesand filter frames which are adapted to be moved horizontally andlongitudinally between a stationary frame and a movable end plate;

B. a ram means for pressing said recessed filter plates by said movableend plate during filtering operations and for separating said recessedfilter plates:

C. a plurality of upper rollers, each of which is rotatively attached toand in parallel with an upper horizontal side of one of said recessedfilter plates;

D. a plurality of lower rollers, each of which is parallel with thelower horizontal sides of said recessed filter plates;

E. a washing vessel mounted on said stationary frame and havingrotatably mounted guide rollers;

F. a cloth tautening means which also limits the separation of saidrecessed filter plates by a predetermined distance, comprising aplurality of pairs of pivotal links of equal length, each pair beingpivotably interconnected and rotatively attached, at one end, to theshaft of one of said lower rollers and, at the other end, beingpivotably attached to the lower portions and at the front and rear sidesof:

1. each two adjacent recessed filter plates,

2. said stationary frame and a recessed filter plate adjacent thereto,and 3. said movable end plate and the recessed filter plate adjacentthereto, the length of said links being selected so that the change invertical distance between a vertically related pair of upper and lowerrollers compensates for the changed length of cloth as the press opensor closes, whereby said lower rollers are rotatively disposed at a lowerposition between each two adjacent recessed filter plates; and

G. a continuous filter cloth which is passed sequentially, in zigzagfashion, under and over each of said lower and upper rollers,respectively, and around said guide rollers in passage through saidwashing vessel.

2. The filter press of claim 1, wherein guide rollers are provided abovesaid stationary frame and above said movable end plate and around whichsaid continuous filter cloth passes. I

3. The filter press of claim 2 wherein said cloth is selectivelyreplaced for cleaning in said washing vessel by a motor driving innerand outer chain lines which pass over pairs of drive sprockets and idlewheels on each opposite end of each of said upper rollers and lowerrollers, the inward position relationship of the drive sprocket and idlewheel in each of said pairs being alternately reversed on each twoadjacent rollers.

4. In a horizontal filter press comprising a plurality of filteringelements consisting of alternatively arranged filter plates and filterframes which are adapted to be moved horizontally and longitudinallybetween astationary frame and a movable end plate, a continuous filtercloth, ancl a ram means for pressing said filter plates and filterframes by said movable end plate during filtering operations and forseparating said filter plates and said filter frames, the combinationcompris- A. a plurality of lower rollers, each of which is rotativelyattached to and in' parallel with a lower horizontal edge of one of saidfilter plates;

B. a plurality of upper rollers, each of which is rotatively attached toand in parallel with an upper horizontal edge of one of said filterframes;

C. a washing vessel mounted on said stationary frame and havingrotatably mounted guide rollers;

D. a cloth tautening means which comprises:

1. a guide plate, having a slot therein, which is horizontally andlongitudinally mounted on said movable end plate,

2. a pressure-operated fluid cylinder means which is mounted on saidmovable end plate, and

3. A tension roller which is rotatably attached to said fluid cylindermeans and which is slideably attached to said guide plate,

E. a continuous filter cloth which is passed sequentially, in zigzagfashion, under and over each of said lower and upper rollers,respectively, around said guide rollers in passage through said washingvessel, and around said tension roller, whereby said fluid cylindermeans moves said tension roller backward, thereby keeping said clothtaut when said ram means pushes said movable end plate forward to bringsaid alternatively arranged filter plates andfilter frames together forfiltration, and moves said tension roller forward, thereby selectivelyloosening said cloth when said ram means retracts said movable end plateto release said filter plate and filter frames; and

F. a sequential opening and closing means for limiting the separation ofsaid filter plates and said filter frames by a predetermined distance,comprising:

7 v 8 l. a projection on opposite sides of each filter I c. the movableend plate and the filter plate adplate, each filter frame, saidstationary frame, jacent thereto, so that said filter plate and said andsaid movable end plate; and filter frame are brought together orseparated 2. a bolt which connects together each two projecm h h r nafter the oth i lm tions in facing relationship on: cloth being passedalong said lower roller ata. each adjacent filter plate and eachadjacent tached each of 581d P (We! filt r f I said upper roller mountedon each of said b. said stationary frame and the filter frame adfilterIn a 8 8 mannerjacent thereto, and lo

1. A horizontal filter press comprising: A. a plurality of recessedfilter plates serving as both filter plates and filter frames which areadapted to be moved horizontally and longitudinally between a stationaryframe and a movable end plate; B. a ram means for pressing said recessedfilter plates by said movable end plate during filtering operations andfor separating said recessed filter plates; C. a plurality of upperrollers, each of which is rotatively attached to and in parallel with anupper horizontal side of one of said recessed filter plates; D. aplurality of lower rollers, each of which is parallel with the lowerhorizontal sides of said recessed filter plates; E. a washing vesselmounted on said stationary frame and having rotatably mounted guiderollers; F. a cloth tautening means which also limits the separation ofsaid recessed filter plates by a predetermined distance, comprising aplurality of pairs of pivotal links of equal length, each pair beingpivotably interconnected and rotatively attached, at one end, to theshaft of one of said lower rollers and, at the other end, beingpivotably attached to the lower portions and at the front and rear sidesof:
 1. each two adjacent recessed filter plates,
 2. said stationaryframe and a recessed filter plate adjacent thereto, and
 3. said movableend plate and the recessed filter plate adjacent thereto, the length ofsaid links being selected so that the change in vertical distancebetween a vertically related pair of upper and lower rollers compensatesfor the changed length of cloth as the press opens or closes, wherebysaid lower rollers are rotatively disposed at a lower position betweeneach two adjacent recessed filter plates; and G. a continuous filtercloth which is passed sequentially, in zigzag fashion, under and overeach of said lower and upper rollers, respectively, and around saidguide rollers in passage through said washing vessel.
 2. said stationaryframe and a recessed filter plate adjacent thereto, and
 2. The filterpress of claim 1, wherein guide rollers are provided above saidstationary frame and above said movable end plate and around which saidcontinuous filter cloth passes.
 2. a pressure-operated fluid cylindermeans which is mounted on said movable end plate, and
 2. a bolt whichconnects together each two projections in facing relationship on: a.each adjacent filter plate and each adjacent filter frame, b. saidstationary frame and the filter frame adjacent thereto, and c. themovable end plate and the filter plate adjacent thereto, so that saidfilter plate and said filter frame are brought together or separatedfrom each other one after the other, said filter cloth being passedalong said lower roller attached to each of said filter plates and oversaid upper roller mounted on each of said filter frames in a zigzagmanner.
 3. A tension roller which is rotatably attached to said fluidcylinder means and which is slideably attached to said guide plate, E. acontinuous filter cloth which is passed sequentially, in zigzag fashion,under and over each of said lower and upper rollers, respectively,around said guide rollers in passage through said washing vessel, andaround said tension roller, whereby said fluid cylinder means moves saidtension roller backward, thereby keeping said cloth taut when said rammeans pushes said movable end plate forward to bring said alternativelyarranged filter plates and filter frames together for filtration, andmoves said tension roller forward, thereby selectively loosening saidcloth when said ram means retracts said movable end plate to releasesaid filter plate and filter frames; and F. a sequential opening andclosing means for limiting the separation of said filter plates and saidfilter frames by a predetermined distance, comprising:
 3. said movableend plate and the recessed filter plate adjacent thereto, the length ofsaid links being selected so that the change in vertical distancebetween a vertically related pair of upper and lower rollers compensatesfor the changed length of cloth as the press opens or closes, wherebysaid lower rollers are rotatively disposed at a lower position betweeneach two adjacent recessed filter plates; and G. a continuous filtercloth which is passed sequentially, in zigzag fashion, under and overeach of said lower and upper rollers, respectively, and around saidguide rollers in passage through said washing vessel.
 3. The filterpress of claim 2 wherein said cloth is selectively replaced for cleaningin said washing vessel by a motor driving inner and outer chain lineswhich pass over pairs of drive sprockets and idle wheels on eachopposite end of each of said upper rollers and lower rollers, the inwardposition relationship of the drive sprocket and idle wheel in each ofsaid pairs being alternately reversed on each two adjacent rollers. 4.In a horizontal filter press comprising a plurality of filteringelements consisting of alternatively arranged filter plates and filterframes which are adapted to be moved horizontally and longitudinallybetween a stationary frame and a movable end plate, a continuous filtercloth, and a ram means for pressing said filter plates and filter framesby said movable end plate during filtering operations and for separatingsaid filter plates and said filter frames, the combination comprising:A. a plurality of lower rollers, each of which is rotatively attached toand in parallel with a lower horizontal edge of one of said filterplates; B. a plurality of upper rollers, each of which is rotativelyattached to and in parallel with an upper horizontal edge of one of saidfilter frames; C. a washing vessel mounted on said stationary frame andhaving rotatably mounted guide rollers; D. a cloth tautening means whichcomprises: